The proposed research applies life-course theory as an innovative framework to study health and personality development in a unique longitudinal study, from birth to age 31. With regard to health, specific hypotheses address the processes by which cumulative pathways of adversity and advantage during the first 30 years of life shape adult health. We also test whether psychosocial experiences between childhood and adulthood affect within-individual changes in health. With regard to personality, specific hypotheses address how work and relationship experiences affect men's and women's personality development as they make the transition from adolescence to adulthood.The proposed research is innovative both in the fields of health and personality psychology. With regard to health, we will advance theory by applying a life-course perspective to understanding the emergence and persistence of health inequalities. Findings will inform primary prevention programs by identifying the developmental origins of specific "pre-clinical" health conditions that have demonstrable disease relevance. With regard to personality, we will challenge the dominant paradigm of personality continuity that has fostered pessimism about the potential for change, and provide a strong methodology for testing hypotheses about how psychosocial experiences influence the nature and direction of personality change during the transition from adolescence to adulthood.